It has been known for many years that if a grain harvester or header cutting platform is fitted with a low pressure centrifugal blower or compressor and manifold, having a number of outlet tubes the openings of which face rearwardly and are situated forwardly of the cutter bar assembly, the cut crop can be assisted in its movement over the cutting platform and into the feed auger at the rear end thereof. This arrangement is intended to eliminate the need for a reel on "open" machines or the knife auger or flail on "closed" front headers, but the system has not come into use because of the difficulty of satisfactorily transporting the cut crop to the main throat of the machine for further processing.
Another difficulty which has been encountered has been a very considerable loss which has been occasioned on prior art machines wherein the air discharge tubes are positioned forwardly of the cutter bar assembly, due to "shatter" of the crop if harvested under dry conditions. For example, in the U.S. Pat. No. 2,670,586 (C. M. Phillips) there is described and illustrated a pneumatic attachment having pipes which depend from a manifold and terminate at their lower ends in fan shaped air nozzles. These are located forwardly of a cutter bar assembly, and in use under very dry conditions would so interfere with a standing crop as to cause considerable loss due to "tailing in" by forcing the crop to go under the fan shaped nozzle and to "shatter". However it is deemed desirable to harvest crops under dry conditions to ensure a low moisture content of the grain, and at the time of writing this specification, official figures in Australia indicate an average loss of about $8.00 per acre (about $20.00 per hectare) in certain type crops due to the crop being shattered and/or lost over the front end of the cutting platform, even without the use of such devices in front of the cutter bar assembly. This loss is still further increased if there are relativly large obstructions to the crop forward of the cutter bar assembly, for example, as illustrated in said U.S. Pat. No. 2,670,586, and much of the shattered "tailed in" or lost crop is wasted by not passing through the harvester or header machine.
The main object of this invention therefore is to provide an improved system wherein use is made of an air manifold and outlet relatively narrow tubes extending therefrom, arranged and shaped in such a way as to assist the cutting and transporting of the headed crop across the cutting platform of a grain header or harvester so effectively that the need is abolished for use of a reel, and the loss due to shattering of the crop or of grain heads falling over the front of the cutting platform is substantially reduced.